Integer overflow in the sctp_getsockopt_local_addrs_old function in net/sctp/socket.c in the Stream Control Transmission Protocol (sctp) functionality in the Linux kernel before 2.6.25.9 allows local users to cause a denial of service (resource consumption and system outage) via vectors involving a large addr_num field in an sctp_getaddrs_old data structure.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.